Precision laser slicing technology for single-crystal SiC wafer

1^st report : Study on slicing method considering kerf-loss

Abstract

We developed a precision laser slicing technology for single-crystal SiC. To reduce kerf-loss, the mechanism underlying laser mark formation inside the wafer was determined. The laser marks consist of amorphous modified parts and cleavages formed a periodic serrated shape along the off-angle. This phenomenon is caused by interference of laser reflection on the cleavage, resulting in increased laser absorption. Therefore, excess off-angle cleavage growth occurred resulted in increased kerf-loss. Slicing experiments with SiC wafers were carried out taking this mechanism into consideration, and precision laser slicing with kerf-loss < 36 μm was achieved.